Trey's promissory note thread actually made me think of this.
I'd actually love for there to be a secure warehouse where people can store their rare goods or stuff for collection or to facilitate transactions. You see some people using shops as displays more than for actually selling things and it's often the desire for a stockroom (or more specifically a non-decay room) that factors into driving shop prices through the roof.
Personally I just want a place to keep some memorabilia. Occasionally I take things out and cycle them in my house for display, but the cost of non-decaying individual items is crazy when you have so many, and I don't want to put everything on display because that's spammy.
So, I'd like for a sort of trading post/warehouse in Delos. You can keep any number of items you want so long as you're willing to pay the rent for it, and it gets progressively more expensive as you try to hoard more items. For example, you could pay 2k a year to store 5 items, 5k for 10, 12k for 20 and so forth. The rent can be automatically deducted from your account the same way mining fees are.
Should you default on your payments, the items can either be automatically returned to you (merciful) or the debt of rent can be accrued up to a certain level (maybe 50-100k, tiered according to your annual rent perhaps) after which the warehouse will sell or auction your stuff off to the public to settle the debt.